1. Field of the Invention
The present invention relates to a technical field of an electro-optical apparatus such as an active matrix driving liquid crystal apparatus driven by thin film transistors (hereinafter also referred to as TFTs) or the like, and also to an electronic device using the same. More particularly, the present invention relates to an electro-optical apparatus in which data lines are driven at a high frequency by a data line driving circuit provided on a TFT array substrate in response to a control signal such as a clock signal, and also an electronic device using the same.
2. Description of the Related Art
In conventional electro-optical apparatuses such as an active-matrix driving TFT liquid crystal apparatus, a great number of scanning lines and data lines are formed in horizontal and vertical directions, respectively, on a TFT array substrate, and a great number of pixel electrodes are formed at respective intersections of the scanning lines and the data lines. In some cases, in addition to the above elements, other elements are also formed on the TFT array substrate, such as data signal supply means including a data line driving circuit and a sampling circuit or the like and serving to supply a data signal to the data lines, and also a scanning signal supply means including a scanning line driving circuit or the like and serving to supply a scanning signal to the scanning lines.
In this case, a control signal such as a data line side reference clock signal which activates a data line driving circuit indicating a time reference for supplying a data signal, an image signal which corresponds to the content of images to be displayed and which is used as a basis on which the data signal is produced, and positive and negative constant electric potential power-supply or the like are supplied to the data signal supply means via external input terminals and wiring provided on the TFT array substrate, respectively. Similarly, a scanning line side reference clock signal which activates a scanning line driving circuit indicating a time reference for supplying a scanning signal, and positive and negative constant electric potential power-supply are supplied to the scanning signal supply means via external input terminals and wiring provided on the TFT array substrate. In the scanning signal supply means, for example, the scanning line driving circuit supplies a scanning signal over the scanning lines on the line-by-line basis in accordance with the scanning line side reference clock signal. In response, in the data signal supply means, the data line driving circuit drives the sampling circuits, which serve to sample the input image signal, one by one in accordance with the timing indicated by the data line side reference clock signal. As a result, a data signal is supplied from the sampling circuits over the data lines. The respective TFTs whose gate is connected to one of the scanning lines turn on in response to receipt of the scanning signal supplied via the scanning lines. As a result, the data signal is supplied to the pixel electrodes via the corresponding TFTs and thus an image is displayed on the respective pixels.
In recent liquid crystal apparatuses, in particular in those for use in a liquid crystal projector, the frequency of serial image signals becomes increasingly high with the increase in the resolution of the image displayed. For example, the dot frequency of the image signal in the XGA display mode or SXGA display mode employed in recent high-resolution displays for personal computers is about 65 MHZ and 135 MHZ, respectively, which are much higher than the dot frequency in the conventional VGA mode (about 30 MHZ). As a result, a very high frequency is also required for the data line side reference clock signal supplied to the data signal supply means.